Process of producing fermentable sugars.



U ITED srArgsr TENT 1 FRANCIS a. GALLAGHER, or NEWTON, AND nARRY s.MORK, or BOSTON, MASSACHU- sn'rrs, ASSIGNORS TO STANDARD ALcoHoI.COMPANY, or NEW roan, N. Y., a con- IPORATION OF MAINE.

No Drawing.

To all whom it may concern:

Be it known that we, (1) FRANCIS E. GALLAcnEn and (2) HARRY S. Morn,citi- Zens of the United States, residing at (1) Newton and (2) Boston,in the counties of (1) Middlesex I and (2) Suffolk, State ofMassachusetts have invented certain new and useful Improvements inProcesses of Producing Fermentable Sugars, of which the following is aspecification.

This invention relates to processes of producing fermentable tsugarsfrom sawdust, wood-waste or other cellulosic raw material, by the actionof steam in presence of suitable so-called hydrolyzing agents.

According to the preferred embodiment of the process, the cellulosic rawmaterial or wood-waste is introduced in its normally moist conditioninto a digester mounted for rotation, being'thoroughly mixed, either before or after its introduction into the digestor, with a suitablehydrolyzing agent, as for example sulfuric acid or hydrochloric acid inthe proportion of 0.5 to 2.0 per cent. by weight of the charge. Thedigester is set in motion, and steam is introduced into the body of thecharge at appropriate pressure, say seventy to one hundred pounds orsomewhat more per square inch. Under these conditions the wood-wasteundergoes hydrolysis with the production of fermentable sugars as iswell understood, and the digestion is continued for a suit able period,as fifteen to sixty minutes, or until the conversion has proceeded tothe desired extent. During this digestive treatment, portions of thevapors and volatile products arising from the charge or result ing fromthe reaction are permitted to escape from the digester, either into the'air, or preferably into a suitable condensing system, the pressurewithin'the digester being meanwhile sutliciently maintained. Such escapeor withdrawal of the vapors and volatile products may be eithercontinuous or intermittent, and is found to result in a materialincrease in the percentage of fermentable sugars produced underotherwise similar digestive conditions. While the underlying cause orcauses of this observed result are not certainly known, it is nowpresumed that certain volatile products arising during the digestionact, either by tending to the establishment of a chemical equi-Specification of Letters Patent.

Application filed June 6, 1912. Serial No. 702,065.

action is enabled to 'ing intended to guard Patented Aug. 27, 1912.

librium or otherwise, to check or limit the reaction which yields thefermentable sugars; and that by eliminating portions of such wroductscontinuously or at suit-able lIltGlHtLlS during dig ion, the desiredreceed more nearly to completion. There may also occur a betterelimination of volatile products of antisep tic orfermentation-inhibiting character, as for example aldehydes or similarbodies, which, if retained 111 the mass. and in the extract subsequentlyprepared therefromv would have a retarding effect upon the yeast. Therelief of the pressure may also have purely mechanical effects. tendingto increase the yield, as for instance by giving rise to internalebullition tending to a more perfect distribution or action of thehydrolyzing agent.

It is found of volatile matters during the digestion, as abovedescribed, not only is a higher percentage of soluble products obtainedunder digestive conditions otherwise similar, but an increasedpercentage of these soluble products consists of fermentable sugars. Inother words, the pressure-relief affords a direct and substantialincrease in the percentage of alcohol. obtainable, from the cellulosicraw material.

The process may be carried out by the aid of any suitable apparatus, asfor example that shown in the application of George M. Tomlinson, SerialNo. 67 1465, filed Janthat by relieving the pressure being obtained bypartially opening the ,valve between the digester and the condensingsystem.

It will be understood that when resinous Woods are used the digestivetreatment may be preceded, if desired, by a distillation treatment forthe recovery of turpentine or like hydrocarbons. This preliminarytreatment for the, recovery of volatile hydrocarbone is to bedistinguished from the digestive treatment for the preparationoffermentable sugars, to the conduct of which the present inventionrelates. The in'vention is also to be distinguished from the mereprovision of a safety-valve in connection with the digester, suchsafetyvalve beagainst the possibility of such accidental excessiveprcssures and temperatures within the digester as operation.

might have a deleterious efi'ect upon the We claim 1. The process ofproducing fermentable sugars from ligno-cellulose or other cellulosicraw materials, which consists in digesting the material under pressureof products to escape from the digester during the digestive period.

2. A process of producing fermentable sugars from ligno-cellulose orother cellu- M Gupies 0! this patent may be obtained for five centseach, by addressing-the losic raw materials, which consists in digestingthe material in a state of motion underpressure of steam and in presenceof a suitable hydrolyzing agent until fermentable' sugars are formed,and relieving the pressure of the vapors during the digestive period.

In testimony tures in presence of two witnesses.

FRANCIS E..GALLAGHER.

HARRY S. MORYK. Witnesses:

CARL T. Woons, MALCOLM C.

Commissioner 01" Patents Washington, D. O.

whereof, we affix our signa-

